1. Field of the Invention
The present invention relates to an armature of a small motor and, more particularly, to a connecting structure for connecting an end wire of a driving coil wound around a salient pole of a stator core constructed by laminating a plurality of magnetic plates with a lead wire connected to a driving circuit for driving the small motor.
2. Description of the Related Art
Conventionally, a stator core of a small motor is constructed by laminating a plurality of magnetic plates having a plurality of salient poles projecting radially from the peripheral surface of a ring section. An insulating layer is formed on the surface of each of the salient poles of the stator core by coating insulating varnish and driving coils for driving the small motor are wound on the insulating layer of the salient pole. An end wire of each of the driving coils is connected with a lead wire by means of soldering and the like and, through the intermediary of the lead wire, each of the driving coils is connected to an outside driving circuit provided for driving the small motor. Various devices have been developed as the structure for connecting the end wire of the driving coil and the lead wire.
FIGS. 11 and 12 show a prior art example of the connecting structure for connecting an end wire 11 of a driving coil 10 with a lead wire 12.
In FIG. 11, a stator core 2 is constructed by laminating a plurality of ring-shaped magnetic plates 7 having a plurality of salient poles 4 projecting radially from the peripheral surface of a ring section 3. Driving coils 10 are wound respectively around a coil winding section formed on the plurality of salient poles 4; an armature 1 is thus structured.
Each driving coil 10 is sorted into an appropriate number of phases such as three phases of U-phase, V-phase and W-phase and end wires of the driving coils 10 belonging to the same phase are connected in series.
Three end wires at one end of the driving coils 10 (end wires at the winding starting end side, for example) of each of the three phases and one common wire which is what three end wires at the other end (end wires at the winding ending end side, for example) are put together to be common for the three phases, i.e. the total of four wires, are led out as the end wires 11 of the driving coils 10. The lead wires 12 and the end wires 11 are soldered respectively to connect the end wires 11 of both ends of each of the driving coils 10 and the lead wires 12 electrically.
The reference numeral (13) in FIG. 12 denotes a connecting section connected by means of the soldering. The vicinity centered on the connecting section 13 is inserted to an insulating tube 60 to be insulated from the driving coils 10 wound around the coil winding sections of the salient poles 4. As the insulating tube, polyether resin is used for example. The insulating tube 60 is secured in a slot 6 between shade sections 8 of the salient poles 4 by means of press fitting or adhesion.
An adhesive is injected within the insulating tube 60 to rigidly combine the insulating tube 60 and the vicinity centered on the connecting section 13 inserted to the insulating tube 60 or to fix the insulating tube 60 in the slot 6 between the shades 8 of the salient pole 4.
However, because the insulating tubes 60 are small and because all of the insulating tubes 60 have to be treated, it is difficult to complete the assembly. Due to that, sometimes, the insulating tube 60, the end wires 11 of the both ends of the driving coil 10 and the lead wire 12 are not fixed and are treated in a state movable within the insulating tube 60.
According to the prior art connecting method for connecting the end wires 11 of both ends of each of the driving coils 10 and the lead wires 12, the works are carried out by the following steps: pass the lead wire 12 through the insulating tube 60 beforehand; connect the lead wire 12 and the end wire 11 of the driving coil 10 by means of soldering; slide the insulating tube 60 to cover the vicinity centered on the connecting section 13 connected by means of the soldering; and embed the insulating tube 60 into the slot 6 to fix it therein.
However, the prior art method has a disadvantage that it is difficult to complete the assembly steps because, as mentioned above, the insulating tubes 60 are small and also the width of the slots 6 of the small motor is narrow.
Furthermore, the same number of insulating tubes 60 as that of the connecting parts 13 have to be provided and the aforementioned assembly steps have to be carried out on each and every connecting section 13, so that many numbers of small parts are required and the assembly steps become more difficult.